A serpentine pulley kit is one of the most important upgrades you can make on your hot rod.  Which type of serpentine kit do you want? Should you run old-school adjustable brackets with dual belts or a single belt with a spring-loaded tensioner? The old-school adjustable brackets offer a more traditional appearance and can save you some money. A true serpentine system, on the other hand, uses fixed brackets, a single belt, and a spring-loaded tensioner. Either way, modern, multi-rib belt technology is way more reliable and more stable across the rpm range than old V-belts.

A Better Belt

Every once in a while, someone gets really mad and yells at us about how V-belts are better than serpentine belts.  It's kinda weird. The logic goes something like this:  "If my fan belt fails, I can limp the car home by swapping over my power steering belt... A serpentine belt is only one belt, so if it fails, you have zero belts."  We guess that sort of made sense in 1985, before serpentine belts proved themselves so effective. At the same time, if you are still somehow afraid of running a single serpentine belt, you could carry a spare belt in the trunk next to your spare tire. 

Introduced in 1917, V-belts have served us well through two world wars and for many decades. We learned how to adjust them, and we replaced them often. Some folks believe that V-belts are the only way to go and that multi-rib belts are somehow evil.

In reality, multi-rib belts perform better than V-belts and last longer. Multi-rib belts have been proven to last up to 100,000 miles and offer at least 3X the grip of a V-belt (6-rib). The many belt ribs mate up with the many grooves in pulleys for a dramatic increase in surface area. A serpentine belt also leverages the smooth back side of the belt.  Here in 2026, V-belts are really only good for nut-and-bolt period restorations. Beyond that, it's time to make the switch.

Modern Drive Components

It's not all about belt design. Modern belts go hand in hand with modern drive components. Old muscle cars came with 10SI or 12SI alternators.  The design is bulky and relies on a single external cooling fan. Introduced in the mid-80s, the CS130 was engineered with dual fans—one inside and one outside. The added cooling improved reliability. In short, alternators have evolved to meet the demands of high-load systems such as electric fans, electric fuel pumps, and climate control systems. Add in the load from powertrain computers and audio -- which consume very few amps.

Power steering pumps have evolved as well. The old P-Series pumps were famously nicknamed "Canned Hams" because of their shape. Aside from being heavy and taking up a lot of space, P-Series pumps work well enough.

Here at Concept One Pulleys, we use modern GM Type 2 power steering pumps. The Type 2 pump is also a Saginaw design. While officially named the "TC-Series," everyone calls them the Type 2. The design is very simply more compact and therefore easier to package.   We calibrate the pump's pressure and flow characteristics to match your vehicle's steering gear and combination. For example, a Ford Fox-body steering rack requires significantly less pressure and flow than a GM steering box. Hydroboost and other variables can factor into the calibration.

Multi-Rib Drive - Adjustable brackets / multiple belts

Proper multi-rib systems consist of pulleys, adjustable brackets, and drive components. Only the grooved side of the belt contacts the pulleys. Tension is set with adjustable brackets. The supplied 6-rib belts require much less tension than equivalent V-belts. 

You get the benefits of a CS130 alternator with a billet fan, a high-flow aluminum water pump, and a compact power steering pump with a special billet reservoir. If you want air conditioning, step up to a serpentine system. 

Serpentine Drive - Spring-loaded tensioner / single belt

Nothing beats a serpentine drive -- especially when running the maximum number of accessories (water pump, alternator, A/C, power steering). A serpentine drive uses both sides of a single belt—the ribbed and smooth sides. Tension is constantly self-adjusting. If you have ever cranked on a breaker bar to remove a serpentine belt, then you know how much tension is involved.  It takes 30-50 lbs of force to rotate a tensioner.

Fixed brackets are a key structural benefit. A well-engineered serpentine drive system has rock-solid brackets that do not flex. Accessory drive components are HEAVY. An SD7 A/C compressor weighs 10 pounds, for example. It needs to be supported at both ends, or the resulting flex can cause the belt to slip. Be sure to study bracket design when shopping for a serpentine drive system.

Why do good serpentine drives cost $2K-plus? 

We see that comment frequently on Social. "No way I'm paying $2500 for a few pulleys..." Dig a little deeper, and it should become clear that the best systems include everything you need to guarantee perfect pulley alignment, components that work for your vehicle, and bolt-on installation. Concept One LS systems, for example, include SFI balancers. And all Concept One drive systems include Powermaster alternators and brand-name water pumps.

So a good serpentine pulley kit isn't just a set of pulleys. Bracket strength is absolutely critical. There are systems out there that sacrifice strength to cut costs. Concept One systems are engineered for maximum strength with front and rear brackets. 

Proper pulley ratios ensure that drive components don't over-rev or spin too slowly. For example, most alternators are designed with an 18000 rpm limit. So if your engine has a 6000 rpm redline, the pulley ratio must be 3:1. If your engine spins to 7000 rpm, the alternator pulley ratio must be 2.5:1. It's important to work with a serpentine pulley kit manufacturer like Concept One Pulleys that can adapt your pulley ratios to your engine rpm and driving style.

In addition to brackets and pulleys, a proper serpentine pulley kit considers every aspect of the installation, including hardware. Concept One uses bright-finish ASTM A574-grade hardware.  That's the equivalent of grade 8 strength for socket head bolts. It really pays to make sure that your drive kit is all-inclusive.

Both designs work

Ultimately, adjustable bracket systems require a bit more maintenance than true serpentine systems (single belt with a tensioner). Fixed bracket/tensioner systems can be packaged more tightly and can handle more power than adjustable brackets. If you like that old school look and want to save a few bucks, go with adjustable brackets. If you want the ultimate maintenance-free solution, go full serpentine pulley kit.